Effectiveness of denitrifying bacteria in restoring the city black-odorous river's sediment

The effect of different denitrifying bacteria dosages on sediment bioremediation was examined under laboratory conditions, with the black-odorous sediment and water samples collected from Nanning Chaoyang Creek. The results showed that after six weeks of treatment, with denitrifying bacteria dosage of 0.5 g/m(3), sediment thickness reduced for 3.43 cm, and G value increased 3.11 times, for the most. The result from the group with dosage of 0.25 g/m(3), in terms of the above indexes, was second to group with dosage of 0.5 g/m(3) of denitrifying bacteria. Furthermore, for the case with dosage of 0.25 g/m(3), degradation of organic matter was 25.9%, and the chemical oxygen demand, ammonia nitrogen, total nitrogen and total phosphorus removals in overlying water were 76.5%, 94.4%, 87.8% and 79.4%, respectively, slightly higher than those from the group with dosage of 0.5 g/m(3). Therefore, the optimal dosage of denitrifying bacteria was 0.25 similar to 0.5 g/m(3).